hard drive writes permanently

Description

Hello,

I played Anno 1602 with VirtualBox 3.1.0. After some time I think 2 hours my VM (WindowsXP) was freezing. In the status bar the light for the hard drive always glowed red. So I think VirtualBox wrote something on my physical hard drive. The light didn't disappear for several minutes and then the virtual machine froze in. So the window (in Gnome) became gray and didn't react. After this I terminated it.